Froth flotation of ores employing a water-soluble salt of a cymene sulfonic acid



Patented Aug. 3, 1948 Q WATER-SOLUBLE SALT OF SULFONIC ACID A CYMENE William '1. Bishop, Wilmington, Del., assiznor to Hercules Powder Company, Wilmington, Del.,

. a corporation of Delaware No Drawing. Application April 11, 194 5,

Serial No. 587,833

This invention relates to a process for concentrating ores and more particularly to a froth flotation process in the presence of cymene sulfonates.

7 Claims. (ci. 209-160) was retained by an 8 mesh screen. was ground ior'l5 minutes-in a ball mill with 3 lbs. of lime per ton of ore and 1000 cc. of water. The ore contained the minerals, chalcopyrite. chalcocite,

Various sulfates and sulfonates of organic com- 5 pyrite. covellite. and bornite; the gangue matepounds, such as sulfonated castor oil, alkyl-subrials were chiefly feldspar and sericlte. The stituted naphthalene sulfonated acids, and sulground ore was screened through a 48-mesh furic acid esters of normal primary alcohols havscreen and transferred to a 1000 g. flotation maing from 6 to 18 carbon atoms have been sugchine, The pulp was conditioned for 10 minutes gested as flotation reagents Many of these, in l with 0.04 lb. potassium cyanide per n f addition to producing froths, also show some 001- Water was added to dilute the pulp to about lecting properties for several minerals. This is solids. The frother reagent given in Table 1 was a disadvantage because it results in poor selecadded and a sodium dithiophosphate (Aerofioat) tivity of the mineral over the gangue in the ore. type collector was added in an amount equal to These sulfates and sulfonates usually produce a 15 0.08 lb. per ton ofore. Air was drawn. through froth composed of large bubbles which collapse the pulp and a concentrate was scraped oil for under the weight of the mineral film. The vol- 10 minutes. The results are given in Table 1.

' Table 1 Example Fromm at $3 1: cases. are.

Per cent Per cent Per cent 1 p-Cymene sodium sullonate (about.30% inorganlcs). 0. 0. 16 27. 8 82 2 {ggg g zsg m o te(a t s 8:53 M5 2m 84 ume of the froth is diiiicult to control. Immediately after the addition of the frothing agent. a voluminous froth is produced which has a short cell life. The prior art sulfates and sulfonates cause some gangue minerals to be floated and thus result in a low grade concentrate.

It has been found that the above disadvantages are overcome by the use of a water-soluble salt of cymene sulfonic acid as a flotation agent.

These reagents function as frothers and do not EXAMPLES 1-2 A 1010 g. sample of a copper sulfide ore, which The p-cymene sodium sulfonate was prepared by the following method: 50 g. of p-cymene was added drop-wise to 47.7 g, of chlorosulfonic acid at a temperature of 20 C. and then the mixture was agitated and heated at 50 C. The resulting product was neutralized with cc. of 15% sodium hydroxide and 20 g. of sodium carbonate. The water was removed by vacuum distillation and the product dried in a vacuum oven.

Exnmrrrs 3-4 A 1010 g. sample of the copper sulfide ore, described in Examples 1-2, which was retained'on an 8-mesh screen, was ground for 15 minutes oil for 10 minutes. The results are given: in Table 2.

the tailings. a high grade concentrate and a relatively high recovery.

Table 2 Lb. per per Copper in Co per Example Frothe! R0880 Ton g Concentrate Rec very Per cent Per cent Per cent '3 p-Cymene calcium sulionate o. 24 0. 25 21. 7 73 4 p-Cymene sodium sulionate (18-20% lnorganics) 0. 24 0. 26 19. 7 71 Exmus-6 'A flotation pulp of a lead sulfide ore, which is composed of galena with small amounts of pyrite in a dolomite gangue was prepared. A volume of this flotation pulp. corresponding to about 2500 g. of ore. was transferred to a 2000 8. flotation machine. Thenv 0.15 lb. of sodium sulfide per ton ofore, 0.05 lb. of isopropyl xanthate, and the frotherreagent given in Table 3 were added. Air was drawn through the pulp and a concentrate was removed for 10 minutes. The following results were obtained.

- Table 3 toremove the oversize materials.

As shown in the examples, the froth flotation process is carried out in the following manner: The ore or mineral to be concentrated is first finely ground in the presence of water to the desired size, depending upon the mineral to be treated, to insure that all of the gangue and metalliferous components are liberated from each other. The ground mineral is then screened The resulting slurry or pulp is transferred to a flotation machine where it is mechanically agitated. The flotation reagents are added to the pulp either in the mill or in the flotation machine depending on the ore that is treated. Water is added to adjust the pulp to the desired solids content. After the reagents have been dissolved or dispersed, air or other suitable gas is passed through the pulp. The desired mineral collects in the froth that is produced on the surface of the pulp and then the froth is removed.

The frothing agents used in accordance with Lb. er Lead in Lead in Lead 15mph Reagent To Telling Concentrate Recovery 0 Mi H h m m o 05 Per cent Per cent Per cent ens um s one no org cs 5 glg e osote .6 9 7. I l 9 one um s one org cs 6 armood creosote -1 0. 14 n 4 5 that fuming sulfuric acid was used as the sulfonating agent and the inorganic material was removed by extracting the product with alcohol.

, EXAMPLE 7 A 1020 g. sample of a zinc sulfide ore, which was retained by an 8-mesh scren. was ground on a ball mill for :7 minutes with 1000 cc. of water. The zincore was composed of sphalerite. pyrite and a siliceous gangue. The ground ore was screened through a 35-mesh screen and transferred to a 1000 g. flotation machine. The pulp was diluted with water to about 20% solids and conditioned for 10 minutes with 5.5 lbs. of lime per ton of ore'and 1.4 lbs. of copper sulfate per ton of ore. Then 0.16 lb. of ethyl xanthate per ton of ore, and 0.22 lb. of p-cymene sodium sulfonate (about 30% inorganics) per ton of ore were added. Air was drawn through the pulp .and a concentrate removed for 10 minutes. The

tailing contained 0.70% zinc and the concentrate contained 47.0% of zinc; Zinc was recovered in the amount of 96.3%.

From the foregoing examples, it is seen that the present invention provides an improved froth flotation process for separating minerals. The results-show a low percentage of metals in ore, but preferably between 0.01 to 0.5 lb. per

ton of ore. The frothers of this invention function over a wide pH range.

In most cases, it is necessary to use, along with the frother, other reagents in order to obtain an efficient separation of the mineral. These may be collectors, such as xanthates, mercaptans, organic sulfides, thiophosphates, thiocarbonates, thioureas, thiocarbanilide, azo and diazo compounds; activating and conditioning agents, such as copper sulfate and other salts of copper, lead, zinc, alkali metal sulfides, lime, sodium hydroxide, sodium carbonate, cyanides, alkali metal silicates, etc; and inhibitors such as glue, starch, gelatin, tannins, etc. Other well known frothers, such as pine oil, cresylic acid, aliphatic alcohols, etc., may be used in combination with the cymene sulfonates.

The flotation agents disclosed in accordance The frothing agent may contain with this invention may be used generally for the dressing of ores including sulfide ores, oxides, nonmetallic ores and native metals. Coal may be beneflciated by flotation using the cymene suli'onates. The invention is especially applicable,

however, to metallic ores particularly ores con-- taining sulfide minerals of zinc, lead, copper, iron,

silver, etc., which may be simple or complex combinations. 1

Although the applicability of the flotation agent is general for conditioning ores or' treating minerals, the conditions efiecting the frothing opera.- tion are dependent in addition to the froth flotation agent, on the size of the ore being treated, the temperature at which the treatment is pulp; In each case. the particular conditions may be adjusted 'so as to permit the flotation agent to perform in an economical and eflicient manner.

The cymene sulfonates function as frothers and have practically no collection properties for the minerals; thus, they show excellent selectivity for the mineral over the gangue of the ore. By use of these frothing agents the volume of the froth is easily controlled, the bubbles produced are small, the froth has a long cell life, and the percentage of mineral values in the taiiings is low.

Only a small amount of gangue is floated and .ahigh grade concentrate is obtained. Since calcium and magnesium cymene sul-fonates are soluble, these reagents function efllciently in hard water. Relatively small amounts of a, cymene sulfonate are effective in separating the metals from the gangue in an eflicient manner, thereby providing an economical method of concentrating ores.

Patent 18:

What I claim and desire to protect by Letters being carried out and the per cent solldsin the per ton of ore and a collector to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating the said froth.

4. In the method of concentrating ores, the steps which comprise adding between about 0.005 and about 5 lbs. of p-cymene calcium sulfonate per ton of ore'and a collector to an aqueous pulp of the ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating the said froth.

5. In the method of concentrating a zinc sulfide ore, the steps which comprise adding between about 0.005 and about 5 lbs. of p-cymene sodium suli'onate per ton of ore and a collector to an aqueous pulp of said ore, agitating and I aerating said pulp to form a froth containing the desired mineral values of said ore, and separating the said froth.

6. In the method of concentrating a lead sulfide ore, the steps which comprise adding between about 0.005 and about 5 lbs. of p-cymene sodium sulfonate per ton of ore and a collector to an aqueous pulp of said ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating the saidfroth. f 7. In the method of concentrating a copper sulflde ore, the steps which comprise adding between 1. In the method of concentrating ores, the

step which comprises subjecting an aqueous pulp of the ore to froth flotation in the presence of a collector and a water-soluble salt or a cymene sulfonic acid.

2. In the method of concentrating ores, the steps which comprise adding between about 0.005 and about '5 lbs. of a water-soluble salt of 9. cymene sulfonlc acid per ton of ore and a. collector to an aqueous pulp of the cor agitating and aerating said pulp to form a froth containing the desired mineral values of said ore. and separating the said froth.

3'. In the method steps which comprise adding between about 0.005 and about, 5 lbs. 0! p-cymene sodium sultonate of concentrating ores, the

said froth.

about 0.005 and about 5 lbs. of p-cymene calcium sulfonate per ton o1 ore and a collector to an aqueous pulp of said ore, agitating and aerating said pulp to form a froth containing the desired mineral values of said ore, and separating the WILLIAM 'r. BISHOP.

, REFERENCES crrnn The following references are of record in the 'flle of this patent:

' UNITED STATES -PATENTS Number Name Date 1,678,311 Adams July 24, 1928 2,244,512 Brandt June 3, 1941 by Arthur 1". Taggart, T. 0. Taylor and C. R. Ince,

pages 205 to 368. 1030 edition relied on, page 340 OTHER REFERENCES Publication American Institute of Mining and Metallurgical Engineers, Transactions-Milling Methods, "Experiments with Flotation Reagents.

and notes on page 350. (Copy in Div. 25 and Scientific Library.) 

